Cellulose-ether solvent and composition



' To all whom it may comem:

Patented Get. 1?, 1922.

warren stares PATENT. @FFHQE. I

RAY- L. STINCHIFIELD, OF ROCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF-ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

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Ito Drawing.

Be it known that I, RAY L. S'rmonrmm, a citizen of the United States of America, residin at Rochester, in the county ofMonroe an State of New York, have invented certain new and useful Improvements. in

Cellulose-Ether Solvents and Com ositions' (Case B), of which the following is a full, clear, and exact specification.

This invention relates to solvents for making strong solutions of cellulose ether and also relates to the cellulose ether compositions produced by the aid of such solvents.

One object of my invention is to provide a solvent which Wlll dissolve such large proportions of cellulose ethers that thick or viscous flowable solutions maybe obtained for use in plastic and fihn making arts. Another bject of my invention is to rovide a cellulose ether solution which may e manufactured into strong, flexible, transparent film .on the machines and now in use.

In U. S. PatentNo. 1,188,376, Lilienfeld, June 20, 1916, there are disclosed a series of alkyl ethers ofcellulose. Certain of these are practically insoluble in Water, and my invention relates but is not limited to'the ethers having that property. While the ethers may form thin solutions in the esters of the lower monocarboxylic fatt acids and the lower monohydroxy aliphatic alcohols, it has been found that such single solvents by themselves do not dissolve a sufiicient proportion of the ethers to make a desirably thick composition or dope, such as may be used, for instance, in the manufacture of photographic film base by the customary methods, or in the other plastic arts.

I have discovered that adequately strong and useful compound solvents may be prepared by mixing one or more of the esters of the lower monocarboxylic fatty acids and the lower monohydroxy aliphatic alcohols with tetrachloroethane. clude acids and alcohols having less than six carbon atoms in the aliphatic group. The proportions in which the-ingredients are combined may be greatly varied. But I find a useful range to be from 3 to 80 arts of the ester and from 97 to 20 parts of t e tetrachloroethane. Other viscous compositions by the methods By lower I in-;

Application nee use 19, 1921. Serial m. 453,722.

suitable for moulding and similar plastic manipulations may be prepared in which the esters exceed 80% of the compound solvent.

The following examples will indicate useful composltions, but my invention is, of course, not restricted to the details thereof. A vlscous fiowable solution may be prepared by drssolvmglO parts. of water-insoluble ethyl cellulose in 45 parts by weight of tetrachloroethane' and 15 parts by weight of methyl acetate. Another useful film-forming solution may be prepared by dissolving parts of water-insoluble ethyl cellulose in 30 parts of ethyl acetate and 30 parts of tetrachloroethane. I

During film manufacture the volatile esters rap-idly evaporate, so that the film sets quickly enough, yet pitting and wrinkling 1s substantially avoided. Considerable amounts of tetrachloroethane remain in the film and diminish the already small comb ustibility of the ethyl cellulose, besides'imparting a useful degree of additional supplenessto the film. The ingredients are of the ordinary commercial type, sufliciently purified for the process of film manufacture, so as to give a dope yielding films having the proper relative freedom from color. While I mention methyl acetate and ethyl acetate in the esters of acetic acid, propionic acid, butyric acid and methyl alcohol, ethyl alcohol, isop-ropyl alcohol, propyl alcohol, etc.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A compound solvent for ethers of celabove examples, I may employ any of the r lulose, comprisingamixture of tetrachloroethane and an ester of a lower monocarboxylic fatty acid and a lower monohydroxy aliphatic alcohol.

2. A compound solvent for alkyl ethers of cellulose, comprising from 20 to 97 parts by Weight of tetrachloroethane and 3 to 80 parts of an ester of a lower monocarboxylic fatt acid and a lower monohydroxy aliphatic a1 cohol. Y

3. A compound solvent for alkyl ethers of cellulose, comprising tetrachloroethane and ethyl aceate.

4. A thick viscous composition, comprismonocarboxylic fatty acid and a lower ing an ether of cellulose dlSSOlVfid'iIl a mixmonohydroxy aliphatic alcohol. ture of tetrachloroethane and an ester of a 6. A composition of matter, comprising 10 lower monocarboxylic fatt acid and a. lower parts of water-insoluble ethyl cellulose dis- 5 monohydroxy aliphatic alcohol. solved in approximately 30 part-shy weight 15 5, A viscous flow'able film-forming compo- Of tetrachloroethane and 30 parts of ethyl sition, comprising an alkyl ether of cellulose acetate. a dissolved in a compound solvent containing Signed at Rochester, New York, this 16th from 97 to 20 parts by weight of tetrachloreday of March 1921.

10 thane and 3 to 80 parts of an ester of a lower RAY L. STINOHFIELD. 

